The present restrictions on the use of plastic materials in flowline circuits in hazardous areas e.g. on board ships or on offshore platforms are imposed mainly because of the poor fire resistance of these materials relative to metallic materials.
Numerous attempts have already been made to improve the fire resistance of plastic flowlines such as by covering the wall thereof with various types of coatings. During the course of experiments it has been found that many coatings provide a temporary protection to the pipe wall in case of fire but that the coatings tend to fail after exposure to fire during an extended period of time.
An object of the invention is to provide a novel plastic pipe of which the wall is protected against fire even if the pipe is exposed to fire during an extended period of time.